Fiberoptic Sensor System For Hydrocarbon Vapors

Research and development work has been conducted on a fiber-optic hydrocarbon sensor system for use in environmental and process monitoring. The sensing transducer consists of three plastic-clad silica fibers, one with a short section of analyte-sensitive cladding or bare core exposed to the environment. The cores of the three fibers are fused together near their distal ends, which are mirrored to couple light from the input fiber into the other sensing and reference fiber pair. A relatively simple optoelectronic controller is used to excite and interrogate the sensor. The sensor construction and operation of the sensing system are described and results of laboratory and field tests are presented.